This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Zometa will be tolerated and active in patients with recurrent or refractoryneuroblastoma. SPECIFIC AIMS Primary Aims: 1. To determine the maximum tolerated dose of Zometa given as a 15 minute intravenous infusion with a fixed dose of concomitant oral cyclophosphamide when administered in 28 day courses to children with recurrent or refractory neuroblastoma. 2. To determine the toxicities of Zometa given on this schedule. Secondary Aims: 1. To preliminarily evaluate the antitumor activity of Zometa and concomitant oral cyclophosphamide in children with recurrent and/or refractory neuroblastoma within the confines of a Phase I study. 2. To evlauate the pharmacokinetic behavior of Zometa in children with recurrent or refractory neuroblastoma. 3. To obtain preliminary information about the biologic activity of Zometa in neuroblastoma through correlative studies assessing change in markers of bone resorption, cytokines and bone-related growth factors, and gamma-delta T-cells.